Sedimentary dynamics and topographic controls on the tidal-dominated Zagra Strait, early Tortonian, Betic Cordillera, Spain

The approximately 350 m-thick stratigraphic succession of the Zagra Strait records an important oceanographic phase of basin interconnection between the Atlantic Ocean (Guadalquivir Basin) and the Mediterranean Sea through the Betic Cordillera (southern Spain) during the early Tortonian. The Zagra Strait developed as a narrow structurally-controlled marine corridor. The sedimentary dynamics of the Zagra Strait was interpreted from the sedimentological features observed in six sections at well-exposed outcrops. Large-scale (>10 m high) compound and compound-dune complexes moved parallel to the strait margins under strong tidal currents generated by tidal amplification at the strait entrance and exit. Dune distribution can be divided in three sectors with different palaeocurrent migration, lithological and topographical characteristics. The northern and central sectors were separated by a deep depression (>75 m water depth) where tidal currents were weaker and dunes were not generated. The southern sector records a relative decrease in current strength compared with the northern and central sectors, and a significant increase in the bioclastic content in the sediment. Terrigenous content generally increases towards the strait margins, and reciprocally, carbonates towards its axis. The closure of the Zagra Strait resulted from tectonic uplift of that part of the Betic Cordillera before the late Tortonian.

Pengaruh VariasiArus dan Posisi Pengelasan SMAW terhadap Sifat Mekanik Baja ST 37

The purpose of this study was to determine the difference in the value of tensile strength, impact and microstructure test results on ST 37 steel plates due to variations in current strength of 80 A, 85 A and 90 A and 1G, 2G and 3G welding positions. The results of this study show the value of Max.load, current strength of 80 A 3G welding position gets the highest value of 5650 kgf, value of Tinsile strength, current strength of 80 A 3G welding position gets the highest value of 44.78 (kgf/mm2), then the strain value, the current strength of 80 A for the 3G welding position gets the highest value of 0.9% and the value of the modulus of elasticity, the current strength of 80 A for the 3G welding position gets the highest value of 97.94 (GPa,KN/mm2), In the value of the impact test results, the current strength of 80 A is the 1G welding position that gets the highest value, which is 116 Joules. In the observation of microstructure testing, 3 points were carried out, Weld metal, HAZ and Base metal at each strong current

Impact of general anaesthesia on parameters of bulbocavernosus reflex

Dysfunction of the pelvic organs in tumor lesions of the spinal cord is up to 20%. Registration of the bulbocavernosus reflex is performed to assess the integrity of the segmental apparatus of the spinal cord. Polymodal neurophysiological monitoring includes registration of the bulbocavernosus reflex during surgery of spinal cord tumors. The effect of the components of general anesthesia on the parameters of the bulbocavernosus reflex varies significantly according to various medical sources. The aim of the work was to compare the effect of inhalation anesthesia (sevoflurane) and total intravenous anesthesia (propofol) on the parameters of the bulbocavernosus reflex in the surgical treatment of spinal cord tumors. Thirty patients with intradural extramedullary and intramedullary tumors of the spinal cord at the level of Th11–S2 vertebrae were included in the study. The amplitude-frequency parameters of the bulbocavernosus reflex and the threshold intensity of stimulation were assessed in the study. The results of the study demonstrate that intraoperative registration of the bulbocavernosus reflex during resection of tumors of the distal spinal cord can be performed both with inhalation and total intravenous anesthesia. A sustained motor response of the bulbocavernosus reflex requires a higher intensity of stimulation with inhalation anesthesia with sevoflurane than with total intravenous anesthesia. If during the operation the depth of propofol's anesthesia increases by 1 mg/kg/h, then it is necessary to increase the current strength during stimulation by 10–11 mA.

Concurrent Achilles tendon vibration and tibial nerve stimulation to estimate persistent inward current strength in motoneurons

Vibratory (Tvib) and sustained (Tsust) torque responses to concurrent Achilles tendon vibration and neuromuscular electrical stimulation applied over the muscle belly (vib+stim) are used as indicators of motoneuron facilitation and, theoretically, persistent inward current strength. However, neuromuscular electrical stimulation (NMES) applied to the nerve trunk may potentiate motoneuronal excitability more than muscle belly NMES, yet it remains unclear whether NMES applied over the nerve evokes robust Tvib and Tsust responses when used during the vib+stim protocol. This study tested whether a nerve-targeted vib+stim protocol elicits Tvib and Tsust responses in the ankle plantar flexors with acceptable intra- and inter-session reliability. Fifteen men performed the vib+stim protocol with NMES applied over the tibial nerve three times across two sessions; twice in a single session (5-min apart) to test intrasession reliability and then again after 48 h to test intersession reliability. Intraclass correlation coefficients (ICC3,1), within-participant coefficients of variation (CV) and pairwise comparisons were used to verify relative and absolute reliability as well as systematic bias. Thirteen men presented Tvib and Tsust responses (response rate of 87%). Intrasession Tvib and Tsust ICCs were >0.73 but inter-session ICCs were <0.5. Although no systematic bias was detected (p>0.05), both intra- and inter-session CVs were large (>10%) for Tvib and Tsust. The Vib+stim protocol with NMES applied over the nerve evoked Tvib and Tsust in almost all participants, but presented a large intra- and inter-session variability. The method does not appear to be effective for assessing motoneuron facilitation in the plantar flexors.

Influence of the thickness and porosity of the oxide coating on the piston heads depending on the parameters of the microarc oxidation mode

This paper discusses the process of formation of an oxide coating (hardening and heat-insulating coating) on the working surfaces of the head (top and piston grooves) of the piston by the method of microarc oxidation (MAO). In the process of oxidation of the piston head, the operating parameters of MAO will have a significant effect on the thickness and porosity of a formed oxide coating. The paper presents the theoretical relationships between the electrical parameters of the microarc oxidation mode and the thickness and porosity of the oxide coating. The thickness of the formed oxide coating on the piston heads will depend on the applied voltage and the composition of the electrolyte used. The porosity of the formed oxide coating will depend on the parameters of the current strength and the applied voltage. It is theoretically established that the formation of an oxide coating of a certain thickness and porosity occurs due to changes in the current strength, voltage and time of microarc oxidation.

Deposition of fluoropolymer coating on stainless steel surface from plasma of glow discharge

The present work investigates the application of the plasma of glow discharge to deposit the fluoropolymer coatings. Two series of experiments were carried out in which the influence of pressure and current strength on surface coatings morphology during its surface treatment with glow discharge plasma was investigated. The surface morphology is investigated by a scanning electron microscope (SEM), and the water contact angle (WCA) is measured. The fact that the choice of pressure significantly affects the morphology and properties of the deposited coating is established.

Influence of the parameters of the process conditions for microarc oxidation on the formation of the thickness and porosity of the oxide coating

The process of formation of an oxide coating (strengthening and heat-insulating one) on the working surfaces of the piston head (piston bottom and grooves) using the method of micro-arc oxidation (MAO) is discussed. It is noted that during the oxidation of the piston head, the MAO process conditions will have a significant effect on the thickness and porosity of the oxide coating formed. The theoretical dependences of the influence of the electrical parameters of the microarc oxidation process conditions on the thickness and porosity of the oxide coating are presented. It has been found that the thickness of the oxidized layer will be directly proportional to the voltage and composition of the electrolyte, and the porosity is inversely proportional to the voltage and directly proportional to the current strength. It is shown that by varying the parameters of the oxidation conditions (current strength, voltage and process time), oxidized layers of the required thickness and porosity can be obtained.

PRODUKSI GAS HIDROGEN BERDASARKAN PENGARUH LUAS PENAMPANG TERHADAP KONSENTRASI LARUTAN ELEKTROLIT DAN SUPLAI ARUS DENGAN METODE ELEKTROLISIS

Pengembangan energi terbarukan menjadi fokus perhatian saat ini penggunaan sumber energi yang ramah lingkungan dan zero emission dengan pemanfaatan air untuk prosess pembuatan hidrogen melalui proses elektrolisis. Hidrogen adalah gas ringan (lebih ringan dari udara), tidak berwarna dan tidak berbau, jika terbakar tidak menunjukkan adanya nyala dan akan menghasilkan panas yang sangat tinggi, sehingga hidrogen mempunyai potensi yang sangat besar untuk dikembangkan sebagai sumber energi alternatif. Penelitian ini bertujuan untuk menganalisa pengaruh luas penampang dan konsentrasi larutan elektrolit dengan variasi suplai arus listrik terhadap produksi gas hidrogen dengan metode elektrolisis. Larutan elektrolit yang digunakan adalah larutan air garam (NaCl) dengan berlandaskan pada kadar salinitas air laut. Berdasarkan penelitian yang telah dilakukan membuktikan bahwa semakin tinggi konsentrasi larutan elektrolit , semakin besar luas penampang dan semakin tinggi arus yang disuplai maka volume gas yang dihasilkan akan semakin banyak. Hasil yang diperoleh yaitu volume gas H2 tertinggi pada konsentrasi salinitas 35 ppt , elektroda ukuran 0,5 in dan kuat arus 35 ampere sebesar 2,118693 liter gas H2 dalam waktu 120 detik. efisiensi tertinggi didapat pada ukuran elektroda 2,0 in ,salinitas 35 ppt dengan kuat arus 15 ampere nilai yang didapat 99,16% dan daya tertinggi dicapai pada 406 watt pada ukuran elektroda 2,0 in, salinitas 35 ppt pada kuat arus 35 ampere The development of renewable energy is currently the focus of attention on the use of environmentally friendly energy sources and zero emission by utilizing water for the hydrogen production process through the electrolysis process. Hydrogen is a light gas (lighter than air), colorless and odorless, if it burns it does not show a flame and will produce very high heat, so hydrogen has enormous potential to be developed as an alternative energy source. This study aims to analyze the effect of cross-sectional area and concentration of electrolyte solution with variations in the supply of electric current to the production of hydrogen gas by electrolysis method. The electrolyte solution used is a salt water solution (NaCl) based on the salinity of seawater. Based on the research that has been done, it is proven that the higher the concentration of the electrolyte solution, the greater the cross-sectional area and the higher the current supplied, the more gas volume will be produced. The result obtained is the highest H2 gas volume at salinity concentration of 35 ppt, electrode size of 0.5 inchi and current strength of 35 ampere of 2.118693 liters of H2 gas in 120 seconds. the highest efficiency is obtained at the electrode size of 2.0 inchi ,salinity 35 ppt with a current strength of 15 ampere the value obtained 99.16% and the highest power achieved at 406 Watts at the electrode size of 2.0 inchi, salinity 35 ppt at the current strength of 35 ampere

Physicochemical mechanisms of the growth of oxide crystals on the surface of tungsten conductors heated by electric current

Physical and mathematical modeling of stationary thermal modes of heating and oxidation of tungsten conductors heated by electric current in air has been carried out. The dependences of the stationary temperature of the conductor on the strength of the heating current are obtained. The critical values of the current strength are found, which determine the transitions to the unsteady oxidation regime. The results of calculating the temperature regimes describe well the experimental data obtained by us using the electrothermographic method. As a result of experimental studies, the features of the appearance and growth of crystalline oxide structures on the surface of an oxidizing tungsten conductor have been studied. The temperatures at which filamentous crystals appear on the tungsten surface are determined, and the regularities of their growth are investigated. A physicochemical mechanism of the formation and growth of crystalline oxide structures on the surface of a tungsten conductor is proposed. It was found that carbon particles, which are part of the impurity, are the reason for the formation of nitrate crystals of tungsten trioxide on the basic oxide. With an increase in the temperature of the sample, the filaments grow, branch out and transform into dendritic structures of a complex bush-like shape. It has been proven that the rapid growth of crystal structures occurs due to the deposition of clusters and microgranules of WO3 oxide from the gas phase on the crystallization centers on the surface of the conductor. At the initial stage, these are impurity particles or mechanical inhomogeneities of the basic oxide, then a growing crystal. Clusters arise due to large temperature gradients at the surface of the conductor. It has been established that carbon atoms can migrate along the branches of oxide crystal structures. It was found that at the initial stage the crystals grow more intensively in the longitudinal direction. However, upon reaching a certain height, they begin to expand intensively in the transverse direction. The growth rates of crystal structures in the longitudinal and transverse directions are found.

Study on the Optimization of Filling Ratio and Strength Variation Characteristics of Cemented Backfills Containing Fly Ash

The fly ash for underground filling can effectively utilize solid waste, improve the strength of the backfill, and reduce the cost, thus creating good social and economic benefits. Relying on the filling requirements of a gold mine in Jilin, this paper carried out the filling ratio experiments containing fly ash and analyzed the reasons for the variation of the backfill strength based on the hydration characteristics of cement and fly ash and scanning electron microscope. The results show that fly ash has an overall effect on the strength of the backfill, and the strength development is mainly concentrated in the period of 28–56 d; when the filling slurry contains tailings, the excessive amount of fly ash is likely to cause a large number of fine particles to obstruct the hydration of cementitious materials; when the concentration of the filling slurry is 74%, the cement content is 5%, the mass ratio of waste rock-tailings-fly ash is 6:2:3, and the CaO content is 6:3, the strength of the backfill is significantly higher than the current strength of the backfill of the mine, and the cost can be saved by RMB 0.56 per cubic meter; the strength characteristics of the backfill mainly depend on the pore structure; when the filling slurry is better matched, the cement and fly ash hydration generates a large number of C-S-H gel particles, which wraps the aggregate to form a dense structure with less pore structure, and the strength of the backfill increases; the strength variation process of backfill containing cement and fly ash is divided into cement hydration period, fly ash infiltration period, and slurry hardening period. To enhance the strength of the backfill, it is necessary to determine the appropriate cementitious material ratio to maximize the excitation of fly ash hydration during the fly ash infiltration period, and the hydration produces a gel structure with an excellent aggregate ratio. In addition, the slurry hardening reduces the porosity of the backfill. The results can provide basic data and theoretical guidance for further promotion and application of fly ash in mine filling.